Articles & guides
Plain-English explainers on the ideas behind the tools — finance, health and everyday numbers.
IT & Networks · 7 min
Subnetting explained: how to split a network by hand
The block-size method, the magic-number shortcut and a full VLSM worked example — subnetting without the guesswork.
Developer · 7 min
Logic gates and boolean algebra: from truth tables to adders
Seven gates, three laws and one surprising fact: every circuit ever built can be made from NAND alone.
Kitchen Lab · 7 min
Kitchen chemistry: four reactions worth understanding
Fizzing bicarbonate, curdled milk, caramel and whipped egg white — what is actually happening, and the one idea they share.
Physics · 6 min
The pendulum and simple harmonic motion: where the formula stops working
Why a pendulum keeps time, why its mass makes no difference, and exactly how wrong the textbook formula gets at wide angles.
Health · 3 min
Your due date is a five-week window
A due date is one day picked from a 35-day range of normal outcomes — and a longer cycle moves it.
Health · 2 min
Pace, speed and what a race prediction is worth
5:30/km is 10.9 km/h and 8:51 per mile — and a 10K time predicts a slower marathon than even splits suggest.
Health · 3 min
How much water you actually need
Food supplies 20–30% of your intake, sweat can double the requirement, and drinking far too much is its own risk.
Maths · 3 min
The discriminant, the GCD and the order of operations
Whether an answer exists, whether a fraction simplifies, and why −3² is −9 while (−3)² is 9.
Gaming · 3 min
Pity, K/D and win rate: reading game numbers honestly
A 0.6% rate needs 167 pulls on average — and a 60% win rate over 20 games could really be anything from 39% to 81%.
Gaming · 3 min
Sensitivity, frame rate and resolution: the numbers that matter
Why 60 to 144 fps is a far bigger jump than 144 to 240, and why your sensitivity number means nothing in another game.
Engineering · 3 min
Pressure and flow: depth, area and the Reynolds number
A standpipe three metres tall pushes as hard as a reservoir three metres deep — and why 2,300 changes a pipe into a different pipe.
Engineering · 4 min
Stress, strain and stiffness: what actually fails
Stress is not force and stiffness is not strength — and the two properties lead you to different materials.
Engineering · 4 min
Force, work, energy and power: one chain of ideas
Five separate calculators, one chain of physics — and why doubling a car's speed quadruples the energy you have to get rid of.
Engineering · 4 min
The resistor spec nobody checks until it burns
The colour bands give you value and tolerance and say nothing about power — which is the specification that actually destroys parts.
Finance · 4 min
SIP, SWP and lump sum: what the plans actually do
Three products, one piece of arithmetic. What averaging really buys you, why the step-up matters most, and where withdrawal plans get risky.
Engineering · 7 min
Units: where engineering answers go wrong
Most wrong answers are not wrong physics — they are millimetres entered where the formula wanted metres.
Psychology · 7 min
What an online self-test can and cannot tell you
Why your score moves week to week, why types are not traits, and where these quizzes do real harm.
Developer · 7 min
What actually makes a password strong
Length beats complexity, substitutions fool nobody, and reuse is the risk that actually gets people.
Developer · 7 min
What a matching hash actually proves
Integrity, not authenticity — and why MD5 and SHA-1 survive only as corruption checks.
Everyday · 7 min
Mean, median or mode: which average do you want?
Three calculations wearing one name. The gap between them is the most useful signal in the data.
Health · 7 min
Sleep cycles: why when you wake matters
Six hours ending cleanly can beat seven that stop mid-deep-sleep. But duration still matters more.
Construction · 7 min
How to measure a room for materials
When to subtract openings, why a flat 10% waste allowance is wrong, and why batch numbers matter.
Time & Date · 7 min
Why adding a month to a date is ambiguous
There is no 31 February, so an answer has to be invented — and implementations disagree by days.
Construction · 6 min
Concrete quantities: bags, cubic metres and tonnes
One slab, four units — and which one your supplier wants.
Health · 6 min
Macros explained: turning calories into grams
Why 4, 4 and 9 calories per gram decides every macro split.
Gaming · 5 min
Stacks, shulkers and chests: sizing a build order
Every Minecraft quantity is a division by 64. Here is the ladder.
Writing · 5 min
Word count, reading time and the limits people enforce
Reading time is words ÷ 200 — and most limits count characters.
Encoding & Data · 6 min
Base64, URL encoding, hashing: which do you need?
Two are reversible, one is not, and none of them is encryption.
Time & Date · 5 min
Working days vs calendar days: where deadlines go wrong
Ten working days is not two weeks — and today may not count.
Maths · 5 min
Fractions, percentages and ratios are the same idea
One relationship, three notations — and the 3:4 trap.
Gaming · 5 min
What Robux are actually worth
Retail price, the 30% marketplace cut and the DevEx rate — three prices, one Robux.
Construction · 5 min
Waste allowance: why you always order more
Where the waste goes, and why whole-box rounding beats the percentage.
Education · 5 min
How weighted grades really work
Weighted averages, the mark you need on the final, and why GPA is the same sum.
Everyday · 7 min
Metric vs imperial: converting without errors
Why the two systems cause so many slip-ups, and the conversions worth memorising.
Everyday · 7 min
Markup vs margin: the pricing mistake
Why a 50% markup is only a 33% margin — and how to stop it eroding profit.
Everyday · 7 min
Percentages made simple
The three questions percentages answer, and a trick that makes them effortless.
Health · 7 min
Heart-rate zones: training by the numbers
What each zone does, why most training should be easy, and how to find yours.
Health · 7 min
How many calories you actually need
What TDEE means, how activity multiplies it, and how to turn it into a goal.
Finance · 7 min
VAT explained: adding it vs removing it
Why you divide rather than subtract to strip VAT out of a gross price.
Finance · 7 min
How income tax bands really work
Why a pay rise always leaves you better off, and what your effective rate is.
Finance · 7 min
Compound interest: why time beats timing
How compounding works, and why starting early beats saving more later.
Health · 7 min
How to read your BMI correctly
Why BMI is a useful starting point — not a verdict — and what to check alongside it.
Finance · 7 min
Understanding loan amortisation
Where every repayment actually goes, and how to pay less interest overall.
Finance · 4 min
A plain-English guide to mortgages
Repayment vs interest-only, fixed vs variable, and the real cost of buying a home.